What it mean code p440 - Envoy GMC Cars & Trucks

https://www.fixya.com/cars/t19464249-evap_vent_valve_solenoid_location

You need a Catalytic converter and possibly a Evap. cannister

Check the distributor cap for cracks.

the code ur are getting on your envoy is a emiision problem first you could try a new gas cap its a known problem in setting this code ...hope this helps

Answered the other similar question

under the rear of the vehicle under the trunk

thats a evap code should not turn the car off you are heaving some other issue

The P440 means that Evaporative Emission Control System.
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car code scanner

This code is for an evap system large leak. Could be cause by something as simple as a gas cap or by a bit more complex stuck open vent solenoid. Make sure your gas cap o-ring isnt cracked(dry rotted) if it is replace it also make sure it is on tight. Here is some more info I found on the web. http://repairpal.com/OBD-II-Code-P0440

I believe you mean resetting the Code. You can go to Autozone, Advance, or Oreilys and then can reset this for you, free. Sometimes you can just disconnect the NEG post of your battery and the computer will clear. But most people do not like resetting their clock or radio when you do this.